The present invention relates to a fuel pump for an internal combustion engine, particularly to a fuel pump of the type having a coupling block supported on a cam shaft outside of a pump housing, the coupling block being coupled to the engine by means of a driving gear with a synchronous relationship. The present invention also relates to a method for assembling the fuel pump to the engine with the synchronous relationship.
When a fuel pump is assembled to an internal combustion engine, a cam shaft of the fuel pump must be placed and held in a proper position and coupled to a ring gear supported on an engine crankshaft keeping the above proper position, so that fuel injection may be proceeded at a proper timing in synchronism with the rotation of the engine.
In a conventional fuel pump, therefore, a mark is formed on both a pump housing and a cam shaft (or a coupling block), and the cam shaft (coupling block) is rotated, when assembling, until the mark on the cam shaft coincides with the mark on the pump housing and then the coupling block is coupled with the ring gear supported on a crankshaft of the engine through a driving gear, whereby the cam shaft and crankshaft are synchronously connected with each other.
It is very troublesome, however, that the cam shaft of the fuel pump must be rotated till a proper position and held on the position during assembling steps of the fuel pump. As the case may be, it becomes impossible to proceed with the above assembling steps when the marks on either the pump housing or the cam shaft is taken cover by other engine equipments installed in an engine room.